Venting cryosurgical instrument

ABSTRACT

A cryosurgical instrument comprises an applicator pressed into firm contact with tissue to be necrotized, a stream of liquified gas coolant (such as nitrogen) being delivered to the applicator. In one embodiment, the invention provides venting of vapors from the chambers through a vent-extending tube attached to the applicator. In one embodiment, the cryogenic application chamber comprises an open ended chamber connected to a source of pressurized coolant, the distal end of the chamber being open and adapted for application to a subject, the proximal end adapted for connection with the source, there being a vent tube through the wall of the chamber near the proximal end. Another embodiment employs a closed-wall chamber.

3 United States Patent 1191 1111 3,731,690 Br ne 1 1 Ma 8 1973 54] VENTING CRYOSURGICAL 3,504,674 4 1970 Swenson et a1 ..12s 303.1

INSTRUMENT Primary Examiner-Lawrence W. Trapp [75] Inventor. Michael D. Bryne, Vernon, Conn. Attorney Melvin Pearson Williams [73] Assignee: Brymill Corporation, Vernon, Conn. 221 Filed: Nov. 9, 1971 [57] ABSTRACT A cryosurgical instrument comprises an applicator {21] Appl' 197079 pressed into firm contact with tissue to be necrotized, Related Application Data a stream of liquified gas coolant (such as nitrogen) being delivered to the applicator. In one embodiment, of 0 am ers throug a vent-exten ing tu e attac ed to May 1968' abandoned the applicator. In one embodiment, the cryogenic ap- [52] U S Cl 128/303 1 plication chamber comprises an open ended chamber [51] ln.t.cl. HA6) 17/56 connected to a Source of pressurize d coolant the [58] Fie'ld 400 distal end of the chamber being open and adapted for application to a subject, the proximal end adapted for connection with the source, there being a vent tube through the wall of the chamber near the proximal [56] References cued end. Another embodiment employs a closed-wall UNITED STATES PATENTS chamber; 3,411,483 11/1968 Canoy ..128/303.1 X 4 Claims,4 Drawing Figures VENTING CRYOSURGICAL INSTRUMENT CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of my abandoned application Ser. No. 886,260 filed on Dec. 18, 1969, which is in turn a continuation-in-part of my abandoned application Ser. No. 728,536, filed on May 13, 1968.

A cryosurgical delivery system capable of delivering liquified gas coolant to and venting vapor from application means in accordance with the present invention is disclosed in U. S. Pat. No. 3,534,739 of the same inventor entitled CRYOSURGICAL DELIVERY AND AP- PLICATION OF LIQUIFIED GAS COOLANT.

BACKGROUND OF THE INVENTION 1 Field oflnvention This invention relates to cryosurgery, and more particularly to methods and means for venting chambers which receive liquified gas coolant.

2. Description of the Prior Art The use of liquified gas coolants to freeze tissue, and thereby necrotize the same, has long been known. For instance, one well known liquified gas coolant is liquid nitrogen. This and other coolants have been applied in a variety of ways to living tissue which is to be necrotized. One way is dipping ofa swab into the liquid and applying the liquid to the tissue with the swab. However, this method is useful only in dermatological applications, and even then has value only for very small lesions due to the low rate of heat exchange which is possible thereby. Another method is dipping of a metallic element in the nitrogen so as to cool the element, and thereafter applying the element to the lesion. This too is useful only for small lesions, and only where access to the lesion is unlimited.

More recent advances in the cryosurgical arts provide for the constant spraying of liquid nitrogen against the inside wall of a metallic probe, the outside wall of the probe being applied directly to the lesion. In the invention of my aforementioned parent applications, an open ended chamber connected to a liquified gas 000- lant delivery instrument is held against tissue which is to be necrotized by freezing, and a stream of liquified gas coolant is delivered directly to the tissue; the area of tissue upon which the liquid impinges is completely surrounded and sealed off from the atmosphere by the chamber; vapor from the area under treatment is vented out of the chamber.

In the case of the use of closed applicators as described hereinbefore, vapor which forms within the applicator must be vented; heretofore, this venting has been accommodated in instruments known to the art by means of a vent tube formed integrally with the nitrogen delivery system. In other words, the system that delivers the nitrogen to the applicator includes a passageway for nitrogen flowing to the applicator and an additional passageway to accommodate nitrogen flowing from the applicator. This, of course, means that the nitrogen delivery systems have to be more expensive and complex than a single-tube type system which provides only a single passageway for the delivery of nitrogen to the applicator. Examples of both systems are shown in my aforementioned U.S. Pat. No. 3,534,739. Systems having two passageways (for delivery and vent both) are also embodied in very com plex and expensive equipment, of the type which frequently includes a control console, a temporary storage dewar, and the like.

SUMMARY OF INVENTION The object of the invention is to provide simplified venting of cryosurgical applicators.

According to the present invention, a cryosurgical applicator to which a liquified gas coolant is supplied from a source includes a vent tube disposed on a wall of said applicator and in fluid communication with the chamber containing liquified gas coolant, the vent tube adapted to be lead away from the outside surface of the applicator to vent fluid of said coolant from said chamber away from tissue being treated by said applicator.

In further accord with the present invention, a cryosurgical applicator adapted to be releasibly secured to an instrument which delivers liquified gas coolant thereto from a source, said applicator thereby being interchangeable on said instrument, has vent means disposed directly in a wall of the applicator and in fluid communication with the inside thereof, said vent means venting fluid or said coolant from said chamber.

The invention permits utilization of cryosurgical application chambers which require venting, on instruments which do not have venting provisions included therein.

Other objects, features and advantages of the present invention will become more apparent in the light of the following detailed description of preferred embodiments thereof, as illustrated in the accompanying drawmg.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a partly sectioned, side elevation of one embodiment of the present invention illustrating a simplified cryosurgery coolant delivery apparatus in perspective;

FIG. 2 is a partly sectioned, side elevation view of an applicator in accordance with another embodiment of the invention employing a vent-extending tube;

FIG. 3 is a partly sectioned side elevation view of yet another embodiment of the invention having a closed end wall; and

FIG. 4 is a partly sectioned side elevation view of an embodiment of the invention substantially as in FIG. 3 and including a vent-extending tube.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the drawing, elements which are like elements in the aforementioned parent application Ser. No. 886,260 bear like reference numerals, and similar elements herein bear the same reference numerals primed.

Referring now to FIG. 1, liquified gas coolant is provided by a source which may include a tube 20 which comprises the delivery tube of a cryosurgical delivery unit 21 (shown in phantom in FIG. 1). This unit may take the form of the simpler embodiment fully disclosed in my aforementioned U.S. Pat. 3,534,739. On the distal end of the delivery tube 20, a compression fitting may comprise a female portion 26 and a male portion 28, there being a chamber 30 having a vent hole 32 therein, suitably disposed on the male portion 28. The chamber 30 may comprise a cylinder of stainless steel or other suitable material, and, providing that the male portion 28 of the compression fitting 25 is ofa suitable material, such as brass, the chamber 30 may be silver soldered, or otherwise metallurgically bonded thereto at the junction 34. The chamber 30 is open at the distal or application end 36. As not shown herein (but illustrated in FIG. 8 of said parent application), the male portion of the compression fitting 25 may be provided with a plurality of male threads, and may have an aperture in the wall near the junction 34 where the male portion 28 and the proximal end of the chamber 30 are joined. Though not shown, the chamber 30 may be bent in any convenient fashion so as to permit reaching tissue in hard to get areas, such as at the base of the tongue. The chamber 30 may be of any desired configuration, though a cylinder is simple and effective in most applications.

The position of the vent hole 32 may be adjusted so that vapors can be directed in any desired radial direction simply by loosening the connection between the male portion 28 and the female portion 26 of the fitting 24, rotating the entire unit relative to the delivery tube 20, and then re-tightening the portions 26, 28 together once more.

As shown in FIG. 9, a tube 42 may be pressed into the vent hole 32 so as to lead vapor away from the work area. This may comprise simple plastic tubing of about /a inch diameter, and may be several inches long. Other sizes may be chosen as necessary.

In use, the unit 21 may be operated so as to provide coolant, such as nitrogen, in substantially liquid form in the delivery tube 20, which passes into a confinement formed by the chamber 30 and the tissue closing the distal end 36 of the chamber. Depending on the characteristics of the unit 21, and the manner of operating it, sufficient coolant in liquified form may be pumped into the confinement defined by the chamber 30 so as to fill the confinement with substantially completely liquid coolant. Thus, the tissue adjacent the end 36 is in contact with coolant in its liquid form, which provides an excellent heat exchange due to the heat of vaporization of the liquid coolant. As the confinement tends to fill with liquid, the gases may vent through the vent hole 32. When sufficient coolant exists in the confinement, the unit 21 may be shut off so that no further coolant is added thereto, and in many cases, the amount of coolant needed to fill the confinement would be sufficient to necrotize the lesion involved. It has been found that, due to the extreme cold of the chamber 30 when it has liquid (such as nitrogen) therein, droplets of liquified air will form on the outside of the chamber giving an indication of the level ofthe liquid therein. Thus, particularly in the case when the chamber 30 is inclined at an angle, it becomes a simple matter to determine when the chamber 30 needs a replenishment of liquid coolant.

Another mode of operating the embodiment of the present invention shown in FIGS. 1 and 2 contemplates directing a stream of liquid coolant into the chamber 30 with short bursts thereof from the unit 21. The liquid falls directly on the tissue near the distal end 36 of the chamber 30, and gases resulting from the expansion and warming of the liquid will vent through the hole 32.

In either mode of operation, by running the unit for a short period of time, prior to applying it to the tissue, the distal end 36 can be brought very nearly to the temperature of the liquid coolant (for nitrogen, on the order of minus C) so that when the chamber is applied to the tissue, it will freeze to it, thus sealing the ends so that liquid will not run out of the confinement formed by the chamber 30 and the tissue frozen to the distal end 36 thereof. When freezing is completed, the ice formed at the joint between the end 36 and the tis sue to which it is applied is sufficiently cold that it will shatter easily and the unit can be removed without dif ficulty. On the other hand, a warm saline solution can be applied to the distal end 36 so as to free it from the frozen tissue. In cases where fissures, fistulars or excess blood hamper the freezing of the chamber to the tissue with a gas-tight seal, this embodiment is very useful.

Vented applicators in accordance with the present invention may also be embodiedin the form of closed walled chambers as illustrated in FIGS. 3 and 4, in addi tion to the open ended chamber of FIGS. 1 and 2. In FIGS. 3 and 4, the chamber 30, its fitting 25 and the vent tube 42 are exactly the same as those in FIGS. 1 and 2 except for the fact that the distal end 36' of the chamber 30 is closed by a wall structure 37. This type of closed applicator has heretofore been useable only on cryosurgical instruments which provide venting of the chamber within the instrument itself (such as illustrated-in FIGS. 35 of my aforementioned US. Pat. 3,534,739). However, the present invention (direct venting of a cryosurgical applicator, with or without a tube to extend the vent away from the application end of the applicator) makes it possible to use a variety of closed applicators with a single passageway nitrogen delivery system (such as the type disclosed in FIGS. 1 and 2 of my aforementioned US. Pat. No. 3,534,739).

Although the invention has been shown and described with respect to preferred embodiments thereof, it should be understood by those skilled in the art that various changes and omissions in the form and detail thereof may be made therein without departing from the spirit and scope of the invention.

Having thus described typical embodiments of my invention, that. which I claim as new and desire to secure by Letters Patent of the United States is:

l. A cryosurgical instrument adapted for use in the necrotic freezing of living animal tissue comprising:

a source ofimpelled liquified gas coolant;

an applicator adapted for contact with and having a cross sectional area commensurate with an area of tissue to be frozen, said applicator, when in contact with said tissue to be frozen, providing a V closed chamber for the receiving of liquified gas coolant therein thereby to extract heat from said area of tissue to be frozen, said applicator connected to said source of impelled liquified gas coolant for receiving coolant into said chamber; and

a vent tube disposed on said applicator and in fluid communication with said chamber, said vent tube extending away from the outside surface of said applicator to vent fluid of said coolant from said chamber away from tissue surrounding said area of tissue to be frozen.

2. The cryosurgical instrument according to Claim 1 wherein said vent tube comprises plastic tubing.

3. A cryosurgical instrument adapted for use in the necrotic freezing of living animal tissue comprising:

a source of impelled liquified gas coolant;

an applicator adapted for contact with and having a cross sectional area at a distal end thereof commensurate with an area of tissue to be frozen, said applicator, when in contact with said tissue to be frozen, providing a closed chamber for the receiving of liquified gas coolant therein thereby to extract heat from said area of tissue to be frozen, said applicator releasably connected at its proximal end to said source of impelled liquified gas coolant for receiving coolant into said chamber, said apwherein said vent tube comprises plastic tubing. 

1. A cryosurgical instrument adapted for use in the necrotic freezing of living animal tissue comprising: a source of impelled liquified gas coolant; an applicator adapted for contact with and having a cross sectional area commensurate with an area of tissue to be frozen, said applicator, when in contact with said tissue to be frozen, providing a closed chamber for the receiving of liquified gas coolant therein thereby to extract heat from said area of tissue to be frozen, said applicator connected to said source of impelled liquified gas coolant for receiving coolant into said chamber; and a vent tube disposed on said applicator and in fluid communication with said chamber, said vent tube extending away from the outside surface of said applicator to vent fluid of said coolant from said chamber away from tissue surrounding said area of tissue to be frozen.
 2. The cryosurgical instrument according to Claim 1 wherein said vent tube comprises plastic tubing.
 3. A cryosurgical instrument adapted for use in the necrotic freezing of living animal tissue comprising: a source of impelled liquified gas coolant; an applicator adapted for contact with and having a cross sectional area at a distal end thereof commensurate with an area of tissue to be frozen, said applicator, when in contact with said tissue to be frozen, providing a closed chamber for the receiving of liquified gas coolant therein thereby to extract heat from said area of tissue to be frozen, said applicator releasably connected at its proximal end to said source of impelled liquified gas coolant for receiving coolant into said chamber, said applicator thereby being exchangeable on said source, said applicator having a vent hole near said proximal end and in fluid communication with said chamber, said vent hole adapted to vent fluid of said coolant from said chamber; and a vent tube inserted in said vent hole and in fluid communication with said chamber, said vent tube extending away from the outside surface of said applicator to vent fluid of said coolant from said chamber away from tissue surrounding said area of tissue to be frozen.
 4. The cryosurgical instrument according to claim 3 wherein said vent tube comprises plastic tubing. 